Clamping means for split rotary anvil and the like

ABSTRACT

A clamping mechanism for clamping upon a rotatable shaft a split rotary anvil or the like and comprising cooperating male and female clamping members provided on respective mating ends of the anvil, each male member being pivotally attached to its mating end and having a camming surface engageable by camming means of the respective mating end having a female member.

United States Patent [191 Sauer 1 Mar. 18, 1975 1 CLAMPING MEANS FOR SPLIT ROTARY ANVIL AND THE LIKE [75] Inventor: Louis E. Sauer, St. Louis, Mo.

{73] Assignee: L. E. Sauer Machine Co., St. Louis,

83/698; 287/5203, 110, 111, DIG. 8; 292/111, 256.67, 301; 285/409, 373, 419, 52.04. 24/230 AV, 230 A; 151/44, 57', 403/344, 20, 292, 323, 324, 378

[56] References Cited UNITED STATES PATENTS 402,221 4/1889 287/5203 1,436,743 11/1922 Wild 85/155 2,752,174 6/1956 Frost 285/409 3,285,642 11/1966 Sauer 83/659 3,288,502 11/1966 Romay 403/408 3,541,651 11/1970 Gaylord 24/230 A OTHER PUBLICATIONS Buck T001 Company's brochure, dated July, 1968, entitled: Saber-Tooth" Expanding Mandrel.

Primary Examiner-Werner H. Schroeder Assistant ExaminerConrad L. Berman Attorney, Agent, or Firm-Rogers, Ezell & Eilers [57] ABSTRACT A clamping mechanism for clamping upon a rotatable shaft a split rotary anvil or the like and comprising c0- operating male and female clamping members provided on respective mating ends of the anvil, each male member being pivotally attached to its mating end and having a camming surface engageable by camming means of the respective mating end having a female member.

13 Claims, 8 Drawing Figures CLAMPING MEANS FOR SPLIT ROTARY ANVIL AND THE LIKE The present invention relates generaliy to rotary die cutting, and particularly relates to clamping mechanisms for clamping split rotary anvils, split heads and the like to rotatable shafts.

In the field of rotary die cutting. ea. inthe manufacture of slotted corrugated boxes and the like, material to be cut is fed into the nip of a pair of rotating rollers wherein one roller is equipped with radially extending cutting edges (the rotary die), and the other roller (the anvil) is equipped with a surface upon which the cutting edges qf the die may bear during the cutting operation. The surface of the anvil may be of metal, but more desirably is a replaceable cover of resilient material such as polyurethane plastic and the like. The anvil upon which such a resilient cover may be placed is clamped onto a rotatable shaft, rotational slip between the anvil and the shaft being prevented by the use of slot pins, tongue-and-groove assemblies, or the clamping action alone of the anvil. The rotary die may be fastened to split head members (commonly called T slot heads) which in turn are mounted in similar fashion to a rotatable shaft. See, for example, U.S. Pat. Nos. 3,274,873; 3,282,142 and 3,285,642.

A rotatable shaft may be provided with one or more anvils, T slot heads and the like clamped in succession along its length, and it is important that these members individually be capable of quick and easy removal from the shaft. To accomplish this, these members may be provided in two or more portions (e.g. split" portions). Although rotary movement of such members with respect to the shaft may be constrained by the aforesaid tongue-and-groove assembly or the like, it is also of important that they be clamped securely and tightly to the shaft so as to prevent any rotary or axial movement thereof with respect to the shaft and to permit extremely accurate positioning thereof on the shaft.

U.S. Pat. No. 3,285,642 lmer alia describes split rotary anvils wherein the clamping mechanism includes a hook-spaced latching link, clamping being accomplished by bringing the split anvil members together, hooking the latching link attached to one arcuate anvil portion about a fixed member of an adjacent arcuate anvil portion, and urging by means of a camming device, the arcuate portion into a clamped position about the rotatable shaft. Locking the clamping device, as a safety measure so the anvil cannot accidentaly loosen and come off the shaft, is accomplished by actuating a second camming shaft against the top of the hook shaped latching link. Although this device has yielded acceptable results, a simpler, more easily operated device would be desirable. The split anvil sections should be capable of being clamped together upon a shaft with accuracy and strength, and shouid further be capable of being loosened for movement along the shaft or removed altogether easily and without binding or other problems associated with prior art clamping devices, and should include a lock for locking the clamping mechanism to prevent accidental loosening thereof.

It is thus an object of the present invention to provide a simple, efficient, non-binding clamping mechanism for split rotary anvils and the like.

It is another object of the invention to provide a quick-acting clamping mechanism for split rotary anvils and the like which avoids problems associated with binding or sticking during clamping or removal of split anvils or the like from a rotatable shaft.

It is another object of the invention to provide a clamping mechanism for split rotary anvils and the like which is positive-acting, and which permits the anvil or the iilie to be quickly and easily loosened for movement along a rotatabie shaft.

It is another object of the invention to provide a split rotary anvil or the like including a non-binding clamping mechanism for mounting upon a rotatable shaft.

It is a further object of the invention to provide a clamping mechanism which has a locking feature to prevent accidental loosening of the anvil or the like.

These and other objects of the present invention will be apparent from the following description and draw ing wherein:

FIG. I is a perspective view of a rotatable shaft with an anvil and cover of the present invention clamped thereto; FIG. 2 is a perspective view of respective mating ends of a split anvil of the present invention;

FIG. 3 is an axial view of mating, arcuate portions of the split anvil of the invention ready to be clamped together;

FIG. 4 is a view, partially in cross section and partially broken away, taken along lines 4-4 of FIG. 3, showing the device of the present invention in the open, or un-clamped, position;

FIG. 5 is an axial view, in cross section, taken along lines 5-5 of FIG. 4;

FIG. 6 is a plan view of a rotary camming member shown also in FIGS. 4 and 5',

FIG. 7 is a cross sectional view taken along the lines 77 of FIG. 6; and

FIG. 8 is an enlarged cross sectional view taken along lines 88 of FIG. 6.

Briefly, the present invention relates to a clamping mechanism for clamping together respective mating ends of a split rotary anvil or the like upon a rotatable shaft. The mechanism comprises cooperating male and female clamping members carried by said respective mating ends. Each male member is pivotally attached to its respective mating end and has a camming surface so positioned as to tend to draw the male member from its pivotal attachment when force is applied to the camming surface. Each female member is adapted to receive a respective male member and includes camming means adapted to engage and apply force to the camming surface of the male member thereby clamping the mating ends together. The female members also preferably include locking means operatively coupled to the camming means for preventing movement of the latter after mating ends have been clamped together. In a preferred embodiment, the respective mating ends include respective contact surfaces such that juxtaposition of the contact surfaces together upon clamping tends to bias opposed mating ends apart.

Referring now to FIG. I of the drawing, rotatable shaft 10 is provided with split rotary anvil I2 comprising arcuate portions 14 and 16, the latter being provided with slot 18 to receive key 20 of the rotatable shaft. Mounted on the outer periphery of the anvil is a resilient covering (which may be polyurethane plastic) designated generally as 22. Mating ends 24 and 26 (FIG. 2) of arcuate anvil portions I4 and 16 are provided, respectively, with female and male locking memhers designated as orifice 28 and pin 30. The outer periphery of the anvil may be provided with slots 32 for receiving appropriately shaped portions of the resilient covering. Pin 30 has an annular notch or groove 34 therein adjacent its protruding end 36 to provide a camming surface 38 (as shown best in FIG.

Arcuate anvil portion 16 has an orifice 40 in its mating end 26 within which one end 42 of pin 30 is pivotally attached by means of transverse peg 44 which in turn is press-fitted into transverse hole 46 (FIGS. 4 and 5). With reference to the axis of rotation of the rotation of the rotatable shaft 10, orifice 40 is slightly larger in the radial direction than in the axial direction, thereby permitting the pin 30, prior to insertion into orifice 28, to pivot axially about peg 4-4 as shown by arrow 48. The protruding end 36 of the pin 30 is preferably provided with a slight taper or rounding to permit easy insertion thereof into orifice 28. The size of orifice 40, particularly at its brim 50, limits the pivotal motion of the pin 30. In the most preferred embodiment, the amount of pivotal motion allowed pin 30 is limited so that the protruding end 36 thereof will remain sufficiently within the entrance periphery 52 of orifice 28 so as to permit the tapered end 36 to be guided into the orifice 28 when mating, arcuate anvil portions 14 and 16 are brought together about the rotatable shaft 10. Preferably, the pivotal movement of pin 30 is limited so that the chord of the arc subtended by the protruding end 36 of the pin upon pivotal movement thereof is no greater than (and preferably from about to about 70 percent of) the diameter of the orifice 28 adapted to receive the pin.

The pivotal motion of pin 30 is critical to the present invention. This feature, for example, permits the arcuate anvil portions 14 and 16 to be clamped together and removed without significant binding of the pin 30 in the orifice 28. The pivotal motion of pin 30 provides just enough play to make it easy for even an unskilled worker to quickly mount and remove an anvil of the invention from a rotatable shaft. To assure axial mating precision between the arcuate portions 14 and I6 when mounted on shaft 10, it is desired that the pin 30 be restrained from moving or pivoting axially with respect to the axis of rotation of the shaft. The pin 30 may be provided with a slightly smaller diameter throughout the leading (distal) portion of the protruding end, as shown in FIG. 4, the change in diameter being represented therein at 54. It is preferred, however, that at least a portion 56 of the pin 30 which enters orifice 28 be of a diameter substantially the same (allowing for sliding engagement) as the entrance diameter of orifice 28 so as to again promote precise axial alignment of mating ends 24 and 26.

As shown in FIGS. 3 and 5, mating ends 24 and 26 are preferably provided with respective cooperating contact surfaces shown as planar surfaces 57 and 58 which diverge outwardly from each other when the anvil is clamped about the rotatable shaft. The contact surfaces 57 and 58 are positioned adjacent the inner periphery 61 of the anvil such that clamping of mating ends 24 and 26 together by means of pin 30 tends to pivot surfaces 57 and 58 into planar contact, thus urging opposed matings ends (not shown) of arcuate portions 14 and 16 on the opposite side of the rotatable shaft to separate. Thus, loosening of the clamping mechanism of an opposed pair of mating ends of a split anvil will result in partial separation of these ends (thus cocking the anvil in an open position) due to the cooperation of surfaces 57 and 58 under the clamping force biasing these surfaces together. When cocked open, the anvil may be moved readily along the rotatable shaft. Only a slight divergence of planar surfaces 57 and S8 is necessary. For example, in an anvil having an inner diameter of about I foot and a radial thickness of about 2 inches, the gap at the outer periphery of the anvil caused by the divergence of surfaces 57 and 58 may be l5-20 mils.

In order that the split anvil may be rigidly clamped about a rotatable shaft, it is preferred that the inner diameter of the anvil passing through at least one pair of juxtaposed mating ends be greater than the diameter normal thereto. Thus, when arcuate portions of an anvil are fitted about a rotatable shaft, the mating ends of the arcuate portions will be separated by a small gap, which may, for example, be about 20 mils in width for anvil having about a l2 inch inner diameter.

Mating end 24 of arcuate anvil portion 14 is provided with a through-hole 59 transversely therethrough (axially with respect to shaft 10) bearing a rotatable dowel 60, the ends 62 and 64 of which dowel have hexagonal recesses 66 and 68 therein to receive an Allen wrench to facilitate rotation of dowel. The transverse through hole 59 preferably is enlarged at its ends, the enlarged section accommodating ends 62 and 64 of the dowel being shown generally as 70 and 72, respectively. Along a portion of its length adjacent end 64, the dowel 60 bears a geared surface 82, the purpose of which be explained below.

Slots 74 and 76 are provided respectively in the ends of the dowel 60 to accommodate retaining springs 78 and 80 for retaining the dowel in the through-hole. In one preferred embodiment (not shown) mating surface 1 14 of arcuate end portion 24 is provided with an internally threaded hole extending inwardly to dowel 60 at a point wherein the dowel has a circumferential groove such as slot 76. The internally threaded hole is provided with a screw member threaded therein. The internal end of the screw member is adapted to ride within the circumferential groove in the dowel and to thus restrain the dowel from axial movement thereof within through-hole 59. The external end of the screw member is adapted to extend outwardly from surface 114 a short distance (e.g., /4 inch). The surface of arcuate end portion 26 which mates with surface 114 is provided with a recess therein adapted to loosely accommodate the external end of the screw member. In a two-piece split anvil (having two separate mating halves), only one pair of mating surfaces is provided with the thus-described screw member and recess, thereby insuring that the same mating surfaces are oriented together when the anvil is clamped about a shaft. The screw member is preferably lockingly retained in its threaded hole by a thread sealant or the like so that it cannot be inadvertantly removed.

The dowel 60 is circular in cross section as shown at 84, (FIG. 5) and is so positioned within arcuate end portion 24 as to transversely intersect orifice 28. That length of the dowel 60 which intersects the orifice 28 includes a section which is at least partially circular in cross section on an axis 92 which is off-center but parallel to the axis of rotation 94 of the dowel (FIG. 8). Section 90 has a circular periphery 9! which acts as a camming surface and has a annular transverse groove 96 therein which preferably has a radius approximately the same as the radius of orifice 28. The axis 94 of the dowel 60, the axis 98 of the orifice 28, and the circular groove 96 are preferably so positioned as to permit the surface of the annular groove 96 to become substantially co-planar with the inner circular surface 1000f the orifice 28 when the dowel is rotated to a predetermined position, as d igcus sed more fully below.

The surface of the dowel 60 is also provided at a point along its length adjacent end 62 thereof with circular detent depressions 102 and 104 therein. As shown in FIG. 4, the through-hole 59 bearing circular dowel 60 -is provided at a point alongits length with a spring loaded knob 106, corresponding axially to the location of detent depressions I02 and 104 in the ,dowel. The knob 106 is urged into the detent depression by means of spring 108. The knob and the spring are carried within housing 110 which, in turn, is threaded into hole 112 in the mating surface 114 of arcuate end portion 24. The outer surface of housing 1 is provided with a screw slot 116 for easy removal of the housing and associated spring and knob.

Mating arcuate end portion 24 is also provided with a screw, or rod, 102 threaded transversely therein on an axis which is parallel to and adjacent the axis 94 of dowel 60, as shown in FIG. 4. The screw 120 has a head portion 123 which has a hexagonal recess 122 therein to receive an Allen wrench, a mid-portion 124 of lesser diameter having a smooth surface about which gear 126 may freely rotate, and a threaded end portion 125. The surface of arcuate end portion 24 is recessed to form a shelf 130 upon which gear 126 may hear when screw 120 is turned down, head portion 123 of the screw bearing upon the outer surface 127 of the gear. The teeth'of gear 126 mesh with the teeth of gear 82 of the rotatable dowel 60. Thus, when screw 120 is threaded tightly into arcuate end portion 24, the head portion 123 of the screw forces gear 126 into tight, frictional relationship with ledge 130, thereby preventing gear 126 (and thus gear 82) from turning.

The split anvil or the like of the present invention, of course, comprises at least two arcuate portions which in turn provides two pairs of mating ends which must be locked together. Although it is contemplated that one pair of mating ends may be permanently hinged together, it is preferred that each pair of mating ends be provided with a locking mechanism of the invention.

In operation, the split anvil members [4 and 16 are brought together about shaft 10, the key of the shaft being received within slot 18 of arcuate portion 16, and pin 30 being received within orifice 28. The dowel 60, which had previously been rotated so that the surface of annular goove 96 was presented to orifice 28, is not rotated by means of an Allen wrench so that the circular camming surface 91 of the at least partially annular off-center portion 90 thereof bears against circular groove 38 of pin 30, thereby tending to urge the ends of the arcuate portions together and to lock the pin 30 within the orifice 28. Detents 102 and 104 are positioned relative to the camming surface 9] of dowel 60 to signal positions of the dowel to the person mounting the anvil upon the shaft. When the spring-loaded knob 106 engages detent 102, the surface of circular groove 96 is substantially co-planar with the inner circular surface 100 of orifice 28; this is the position exemplified in FIGS. 4 and 5 of the drawing. Rotation of the dowel in the direction shown by the arrow 107 in FIG. 5 through 90 causes detent 104 to be engaged by the spring-loaded knob [06; in this position, the anvil may be moved along the rotatable shaft upon which it is mounted, but the anvil halves are prevented from separating fully. Further rotation of the dowel causes the camming surface 91 thereof to bear upon annular groove 38 of pin 30 with increasing pressure, clamping the mating ends 24 and 26 of the anvil firmly together. Thereafter, screw is turned down tightly to prevent, by interaction of gears 126 and 82, any further rotational movement of the dowel 60.

It is to be understood that the foregoing description and the accompanying drawing have been given by way of illustration and example. The invention, although described primarily with respect to a split rotary anvil, must be understood to apply as well to split head members and the like. it is also to be understood that changes in the form of the elements or steps, rearrangement of parts or steps, and substitution of equivalent elements or steps, which will be obvious to those skilled in the art, are contemplated as within the scope of the present invention which is limited only by the claims which follow.

What is claimed is:

l. in a split rotary anvil or the like, comprising mating, arcuate members adapted for mounting upon a cylindrical rotatable shaft, a clamping mechanism for clamping mating ends of said arcuate members togehter, at least one mating end having a pin protruding therefrom and pivotally attached thereto for free pivotal movement with respect to said at least one mating end, and the end to be clamped to said at least one mating end having an orifice therein adapted to receive said pin, said pin having a transverse groove adjacent is protruding end to provide a camming surface thereon and the end of said arcuate member bearing said orifice having camming means for engaging and applying pressure to said camming surface after reception of the pin by the orifice, thereby permitting the mating ends to be clamped together, and wherein upon juxtaposition of said mating ends, the inner periphery of said rotary anvil approximates an ellipse with a respective major axis passing through at least one pair of juxtaposed ends and a minor axis being normal thereto.

2. The clamping mechanism of claim 1 wherein said pivotal attachment of said pin permits free pivotal movement thereof in a single plane.

3. The clamping mechanism of claim 2 wherein said single plane is substantially normal to the axis of rotation of said split rotary anvil or the like.

4. The clamping mechanism according to claim 2 wherein the mating end containing said pin has an opening therewith to receive one end of the pin and includes a peg passing transversely therethrough to pivotally attach the pin to said mating end, said opening being sufficiently large to permit said pin to pivot the re within.

5. The clamping mechansim of claim 1 wherein said arcuate member bearing said orifice includes locking means operatively coupled to said camming means for preventing movement of the latter after said mating ends have been clamped together.

6. The clamping mechanism of claim 1 wherein said pin is tapered for easy insertion into said orifice and wherein pivotal movement of said pin is limited so that the chord of the arc subtended by the protruding end of the pin upon full pivotal movement thereof is no greater than the diameter of the orifice adapted to receive said pin.

7. The clamping mechanism of claim 6 wherein pivotal movement of the pin is so limited that said chord is from about 200 to about 70 percent of the diameter of the orifice adapted to receive the pin.

8. The clamping mechanism of claim 1 wherein said pin has a transverse groove of annular cross section therein to provide said camming surface thereon, and wherein said orifice is provided with a rotatable dowel transversely therethrough, said dowel being at least partially circular in cross section within the orifice on an axis which is off-center but parallel with respect to the axis of rotation of the dowel to provide a camming surface adapted to engage said groove in said pin and, upon rotation of the dowel, to bear upon the camming surface of the pin and clamp the same within the orifice.

9. The clamping mechanism of claim 8 wherein that portion of the pin distal of the annular groove therein is substantially circular in cross section, and wherein that portion of the dowel within the orifice has an annual groove therein, the spatial relationship of said dowel and said orifice being such as to permit free insertion of said pin in said orifice past the position of said dowel when the annular groove in the dowel faces the orifice.

10. The clamping mechanism of claim 1 wherein said respective mating ends include respectively cooperating contact surfaces positioned such that juxtaposition thereof upon clamping of said mating ends tends to bias opposed mating ends apart.

11. The clamping mechansim of claim 10 wherein said contact surfaces are planar surfaces diverging outwardly from each other when said split rotary anvil or the like is clamped upon said cylinderical shaft, whereby clamping of said respective mating ends tends to bias said surfaces into planar contact, separating opposed mating ends.

12. In a split rotary anvil or the like, comprising a pair of mating arcuate members adapted for mounting upon a cylindrical rotatable shaft,

a clamping mechanism for clamping mating ends of said arcuate members together, the mating end of one arcuate member having a substantially cylindrical pin protruding from and pivotally attached within an aperture therein for free pivotal movement with respect thereto, the respective diameters of said pin and said aperture being such as to permit pivotal movement of said pin substantially only in a plane normal to the axis of rotation of said arcuate member, said pin having a groove of substantially annular cross section therein adjacent its protruding end, the mating end of another arcuate member having an orifice therein adapted to receive said pin, said orifice having a rotatable dowel transversely therethrough which is at least partially circular in cross section within the orifice on an axis which is off-center but parallel with respect to the axis of rotation of the dowel and the dowel further having a transverse annular groove therein so positioned with respect to said orifice as to permit said pin to be inserted therewithin, said at least partially circular cross section portion of said dowel being adapted to engage said annular groove in said pin upon insertion thereof within said orifice, and, upon rotation of the dowel, to bear upon the annular groove in the pin and clamp the same within the orifice, said dowel further including along a portion of its length adjacent one end thereof, a surface having gear teeth, and wherein said locking means includes a rotatable second gear having teeth which mesh with the teeth of said dowel, and means preventing rotation of said second gear. 13. The clamping mechanism of claim 12 which includes rod means having a head portion, a mid-portion which is of lesser diameter than said head portion and which has a smooth surface about which is rotatably mounted said second gear, and a threaded end member threaded into the end of said arcuate anvil member bearing said orifice, said rod means cooperating with the second gear so as to prevent rotation of the latter when the rod is threaded tightly into the arcuate anvil member. 

1. In a split rotary anvil or the like, comprising mating, arcuate members adapted for mounting upon a cylindrical rotatable shaft, a clamping mechanism for clamping mating ends of said arcuate members togehter, at least one mating end having a pin protruding therefrom and pivotally attached thereto for free pivotal movement with respect to said at least one mating end, and the end to be clamped to said at least one mating end having an orifice therein adapted to receive said pin, said pin having a transverse groove adjacent is protruding end to provide a camming surface thereon and the end of said arcuate member bearing said orifice having camming means for engaging and applying pressure to said camming surface after reception of the pin by the orifice, thereby permitting the mating ends to be clamped together, and wherein upon juxtaposition of said mating ends, the inner periphery of said rotary anvil approximates an ellipse with a respective major axis passing through at least one pair of juxtaposed ends and a minor axis being normal thereto.
 2. The clamping mechanism of claim 1 wherein said pivotal attachment of said pin permits free pivotal movement thereof in a single plane.
 3. The clamping mechanism of claim 2 wherein said single plane is substantially normal to the axis of rotation of said split rotary anvil or the like.
 4. The clamping mechanism according to claim 2 wherein the mating end containing said pin has an opening therewith to receive one end of the pin and includes a peg passing transversely therethrough to pivotally attach the pin to said mating end, said opening being sufficiently large to permit said pin to pivot therewithin.
 5. The clamping mechansim of claim 1 wherein said arcuate member bearing said orifice includes locking means operatively coupled to said camming means for preventing movement of the latter after said mating ends have been clamped together.
 6. The clamping mechanism of claim 1 wherein said pin is tapered for easy insertion into said orifice and wherein pivotal movement of said pin is limited so that the chord of the arc subtended by the protruding end of the pin upon full pivotal movement thereof is no greater than the diameter of the orifice adapted to receive said pin.
 7. The clamping mechanism of claim 6 wherein pivotal movement of the pin is so limited that said chord is from about 200 to about 70 percent of the diameter of the orifice adapted to receive the pin.
 8. The clamping mechanism of claim 1 wherein said pin has a transverse groove of annular cross section therein to provide said camming surface thereon, and wherein said orifice is provided with a rotatable dowel transversely therethrough, said dowel being at least partially circular in cross section within the orifice on an axis which is off-center but parallel with respect to the axis of rotation of the dowel to provide a camming surface adapted to engage said groove in said pin and, upon rotation of the dowel, to bear upon the camming surface of the pin and clamp the same within the orifice.
 9. The clamping mechanism of claim 8 wherein that portion of the pin distal of the annular groove therein is substantially circular in cross section, and wherein that portion of the dowel within the orifice has an annual groove therein, the spatial relationship of said dowel and said orifice being such as to permit free insertion of said pin in said orifice past the position of said dowel when the annular groove in the dowel faces the orifice.
 10. The clamping mechanism of claim 1 wherein said respective mating ends include respectively cooperating contact surfaces positioned such that juxtaposition thereof upon clamping of said mating ends tends to bias opposed mating ends apart.
 11. The clamping mechansim of claim 10 wherein said contact surfaces are planar surfaces diverging outwardly from each other when said split rotary anvil or the like is clamped upon said cylinderical shaft, whereby clamping of said respective mating ends tends to bias said surfaces into planar contact, separating opposed mating ends.
 12. In a split rotary anvil or the like, comprising a pair of mating arcuate members adapted for mounting upon a cylindrical rotatable shaft, a clamping mechanism for clamping mating ends of said arcuate members together, the mating end of one arcuate member having a substantially cylindrical pin protruding from and pivotally attached within an aperture therein for free pivotal movement with respect thereto, the respective diameters of said pin and said aperture being such as to permit pivotal movement of said pin substantially only in a plane normal to the axis of rotation of said arcuate member, said pin having a groove of substantially annular cross section therein adjacent its protruding end, the mating end of another arcuate member having an orifice therein adapted to receive said pin, said orifice having a rotatable dowel transversely therethrough which is at least partially circular in cross section within the orifice on an axis which is off-center but parallel with respect to the axis of rotation of the dowel and the dowel further having a transverse annular groove therein so positioned with respect to said orifice as to permit said pin to be inserted therewithin, said at least partially circular cross section portion of said dowel being adapted to engage said annular groove in said pin upon insertion thereof within said orifice, and, upon rotation of the dowel, to bear upon the annular groove in the pin and clamp the same within the orifice, said dowel further including along a portion of its length adjacent one end thereof, a surface having gear teeth, and wherein said locking means includes a rotatable second gear having teeth which mesh with the teeth of said dowel, and means preventing rotation of said second gear.
 13. The clamping mechanism of claim 12 which includes rod means having a head portion, a mid-portion which is of lesser diameter than said head portion and which has a smooth surface about which is rotatably mounted said second gear, and a threaded end member threaded into the end of said arcuate anvil member bearing said orifice, said rod means cooperating with the second gear so as to prevent rotation of the latter when the rod is threaded tightly into the arcuate anvil member. 